Question

Which one of the following is called pond silk?
A. Spirogyra
B. Volvox
C. Chlamydomonas
D. Euglena

Answer 1

The organism having a filamentous and thread-like body gives the appearance of silk. Silk is always present as fibre and has a shimmering appearance.

Step by step answer: Spirogyra is an aquatic alga. These are mostly found in freshwater reservoirs like lakes and ponds and hence are also called pond scum. Spirogyra has an unbranched body that floats freely on the surface of stagnant water. Its cell wall is made up of two components, cellulose and pectin. The cell wall is double layered with an inner layer of cellulose and an outer layer of pectin. Pectin often dissolves in the surrounding water and from the mucilaginous sheath. This gives spirogyra a slimy and shiny appearance that resembles silk threads. As spirogyra has chlorophyll, they are autotrophic and prepare their own food. For this reason, they are an important part of freshwater ecosystems. Spirogyra reproduces by both sexual and asexual means. They produce by vegetative reproduction also by means of conjugation. Hence, by considering a silk-like appearance given by Hence, the correct answer is A. Spirogyra.
Additional information: Spirogyra has spiral-shaped chloroplast which is helically folded inside the cell and hence the name ‘spirogyra’ was given to it. It reproduces by conjugation. It is a photosynthetic alga and it always grows in clean and fresh water. Some species of spirogyra are eaten as food in various parts of the world.

Note: The spirogyra grows in freshwater sources like ponds, river streams, ditches, and lakes. Spirogyra gives a slimy and shiny appearance. Spirogyra has chlorophyll, they are autotrophic and prepare their own food.